1 . Under a midday summer sun in California’s Sacramento Valley, rice farmer Peter Rystrom walks across a dusty and bare plot of land, dry soil crunching (碎裂) beneath each step. In a typical year, he’d be walking across green rice fields in inches of water. But today the soil is dry and baking in the 35℃ heat. It hasn’t rained for 4 weeks in a row.

“Climate change is expected to worsen the state’s extreme swings in rainfall,” researchers reported in Nature Climate Change in 2018. Low water levels in rivers have forced farmers like Rystrom, whose family has been growing rice on this land for four generations, to reduce their water use.

“If we lose our rice crops, we have to deal with severe food crisis. Climate change is already threatening rice-growing regions around the world. This is not a future problem. This is happening now,” says plant geneticist Pamela Ronald of the University of California, Davis, who identifies genes in rice that help the plant stand up to dryness, disease, flood, etc.

To save and even boost production, rice growers, engineers and researchers have turned to water-saving irrigation (灌溉) routines. Building canal systems and reservoirs (水库) can help farmers dampen their fields. But for some, the solution to rice’s climate-related problems lies in enhancing the plant itself. They hold that establishing rice gene banks that store hundreds of thousands of rice varieties ready to be bred into new, dryness-tolerant varieties is more practical and effective. Solutions may be hidden in the DNA of those older breeds.

Three decades have passed since its initial development, and some researchers are looking beyond the genetic variability preserved in rice gene banks, searching instead for useful genes from other species, including plants and bacteria. But picking genes from one species and putting them into another, or genetic recombination, remains debatable. The most famous example of genetically changed rice is Golden Rice (GR). “Looking ahead, it will be crucial for countries to embrace GR rice. But it will take time,” says Ismail, principal scientist at IRRI,

1. What problem does Rystrom have to deal with?

A．Thirst.

B．Drought.

C．Hot sun.

D．Dusty weather.

2. What can be inferred from Para. 3?

A．Downtrend of rice-growing areas is severe now.

B．Climate change is a threatening factor in the future.

C．Humans will face starvation if crop failure happens.

D．Food crisis is a common occurrence around the world.

3. What’s the purpose of setting up gene banks?

A．To store as many seeds as possible.	B．To cultivate climate-adapted varieties.
C．To improve the efficiency of breeding.	D．To show the technology of gene mapping.

4. What’s Ismail’s opinion about GR?

A．Favourable.

B．Impractical.

C．Disapproving.

D．Insecure.

2 . When micro-plastics end up in farm fields, the pollution can damage plant growth. But two young researchers now report that combining fungi (真菌) with certain farm wastes can partly overcome that problem.

May Shin, 20, and Jiwon Choi, 18, met in a research design class at the Fryeburg Academy, a high school in Maine. May had desired to explore how micro-plastics might affect the ecosystem. Jiwon was crazy about plants and fungi. The young scientists cooperated to test how long-lived plastics might affect farm crops.

Scientists have shown certain fungi can aid root growth and a plant’s nutrient uptake. Those organisms are named arbuscular mycorrhizal fungi (AMF). Certain farm wastes, like straw, can provide nutrients to plants and help stabilize their roots. Such wastes are also known as mushroom substrate (基质) and people often grow mushrooms in them.

May and Jiwon planted over 2,000 scallion (大葱) seeds in pots of soil. Half the seeds got soil polluted with micro-plastics. The rest grew in plastic-free soil. The plants then were further divided into four groups. The young scientists added AMF to the soil in one group. Another group had a top layer of mushroom substrate. A third group got both treatments. The last group got none. For three weeks, the pair tracked how many scallions sprouted (发芽) in each group and measured the plants’ height once each week.

About twice as many scallions sprouted in clean soil compared to that containing plastic bits. But among plants surviving in the polluted soil, a combination of AMF and mushroom substrate helped them out. Those getting both treatments grew 5.4 centimeters per week. That was faster than either of the treatments alone or those getting none.

Jiwon and May then looked at the plant roots with a microscope. Where AMF had been added, it grew into those roots. That increased the scallion roots’ surface area, May said, which should promote their uptake of nutrients. So “I see this project as coming up with a sustainable solution for plant growth in polluted soils,” said May.

1. Why did May and Jiwon work together?

A．To see the effects of long-lived plastics on farm crops.

B．To find the relationship between plants and fungi.

C．To design a research on the growth of plants.

D．To explore the way that the ecosystem works.

2. What is the author’s purpose in writing paragraph 3?

A．To prove the existence of micro-plastics.	B．To compare fungi with farm wastes.
C．To tell the advantages of farm wastes.	D．To provide some related information.

3. What aspect of the study is the fourth paragraph mainly about?

A．Its purpose.

B．Its design.

C．Its findings.

D．Its reasons.

4. How can AMF and mushroom substrate make plants grow faster?

A．By keeping the plants more resistant to pollution.	B．By allowing the plants’ deep area more freedom.
C．By making nutrients more available to the plants.	D．By exposing the roots to a larger surface area.

3 . What if someone told you about a kind of grass as tall as the tallest trees? A grass as strong as steel? Would you believe that person? You should, for that grass is bamboo   (竹子), which has more than 1,000 uses. It is not just a material for making useful products. Young bamboo is eaten, often mixed with other vegetables.

Bamboo grows in many parts of the world. In the USA it grows in many states like Virginia and Florida. Most bamboo, however, is found in wet and warm climates, especially in Asia and on the islands of the South Pacific Ocean.

In most Asian countries, bamboo is nearly as important as rice. This unusual material is used to not only build large buildings but also make water pipes, musical instruments and paper. There are over 1,000 kinds of bamboo. No wonder the lives of nearly half the people on earth would change greatly if there were no longer any bamboo.

1. According to the text, bamboo is actually a kind of         .

A．grass

B．steel

C．tree

D．vegetable

2. Where does most bamboo grow?

A．Only in Asia.	B．Only in the USA.
C．In wet and warm climates.	D．All over the world.

3. What is bamboo used to do in paragraph 3?

A．Build large buildings.	B．Make water pipes.
C．Make musical instruments and paper.	D．All of the above.

4. How many kinds of bamboo are there according to the text?

A．Over 1,000.

B．Over 800.

C．Over 600.

D．Over 400.

4 . Saving Seeds for Next Year’s Flower Garden

Just like vegetable seeds (种子), you can save flower seeds from your garden this year to plant in the following year.

If you want the same kind of flower or plant for next year’s garden, collect only the seeds from plants marked as “heritage”.     1     Cross seeds with a mixture of two different parents will produce new plants, but they will only look like one of the parents. Therefore, you are taking a risk with planting cross seeds.

Even if you expect plants to be the same as their parents, it is not certain. Wind or insects could bring pollen from one plant to another and accidentally create a mixture.     2     But if you like surprises, start experimenting! You could create a lovely new plant or flower!

Just like everything else in gardening, timing is important. Collect seeds on a dry, sunny day.     3     When their pods open, these plants could send their seeds up to 6 meters away. Once on the ground, it is difficult to collect them. Instead, tie a small bag for seed collection over the pod when it nearly opens.

For plants like sunflowers, cut the head off the plant and drop it into a paper bag.     4     This will save your fingers!

You can place the seeds in a glass box that can be sealed. Then store them in a cool, dry area. Make sure to mark your glass box so you do not forget what they are.     5     But you should plant the new seeds the following year for best results.

A．Keep an eye on some flowers.

B．Let the seeds grow and fall naturally.

C．Give the bag a shake to help separate the seeds.

D．When stored with care, seeds are good for several years.

E．These kinds of plants will grow just like their parent plant.

F．In this case, add more seeds to the soil to make sure that some will grow.

G．You can avoid this by planting only the plant from which you plan to collect seeds.

5 . Triantha Occidentalis, commonly known as the western false asphodel (西部假水仙), which has been known to science since 1879, is a herb-like plant found in abundance along North America’s West Coast. But it is only recently that researchers discovered the innocent-looking plant’s desire for insects.

“We had no idea it was carnivorous (食肉的),” says botanist Sean Graham. “This was not found in some exotic tropical location, but really right on our doorstep in Vancouver. You could exactly walk out from Vancouver to this field site.”

While studying the plant, the researchers noticed that Triantha Occidentalis lacked the same gene as other carnivorous plants. Since the plant grows in the same wet, sunny habitat with nutrient-poor soil as other carnivorous plants, they wondered if it caught insects for nutrition as well. “And at the same time they have sticky stems (茎),” Graham said. “So, I wonder if this could be a sign that it might be carnivorous.”

To test whether it is carnivorous, scientists marked fruit flies with nitrogen-15 isotopes (氮-l5同位素). By collecting the plants the fruit flies visited and comparing the nitrogen levels of different plants, the researchers found that Triantha Occidentalis was able to get more than half of the nitrogen it needed, suggesting that it absorbs nitrogen from the fruit flies. Additionally, the digestive enzyme (消化酶) released by the sticky hairs in flower stems was similar to that found in other carnivorous plants.

Usually, the deadly trap of carnivorous plants grow far away from the flower to prevent accidentally killing pollinators (授粉者), while the western false asphodel traps insects near flowers. The scientists say this is the first time they have met the deadly trap on the flower’s stem, and the sticky hairs on the stem of Triantha Occidentalis can only catch small insects, not the larger bees or butterflies involved in pollination.

“It’s a good reminder that we still don’t know much about the ecology of a lot of individual plant species, even in well-known environments,” says Dr. Qianshi Lin.

1. What does Graham stress in paragraph 2?

A．The discovery is made in the local place.

B．Carnivorous plants grow in the hottest places.

C．Triantha Occidentalis is very common.

D．Vancouver is home to various carnivorous plants.

2. What does the underlined word “that” in paragraph 4 refer to?

A．The nitrogen.	B．The digestive enzyme.
C．The flower.	D．The nutrition.

3. Which part of the western false asphodel catches insects?

A．Its fruit.	B．Its leaves.
C．Its stem.	D．Its roots.

4. What is the best title for the text?

A．A new species of local flower is discovered.

B．A carnivorous flower in the wild grows well.

C．A flower gives off strange smell to attract insects.

D．An innocent-looking plant turns out to be carnivorous.